Compared with electrical interconnection technologies using copper wires as media, optical interconnection technologies using fibers or waveguides as transmission media have significant advantages in a transmission rate, a wideband density, power consumption, costs, and other aspects, become a research focus in recent years, and are developed rapidly.
How to implement an optical packet switching (OPS) system having a large capacity, low costs, and a high port density to satisfy many-core communication is still a technical difficulty at present, because an optical network on chip (ONoC) system integrated with an OPS system needs optical buffer, but there are technical bottlenecks in an aspect of optical buffer at present, for example, a small capacity, a large size, and a difficulty in integration. Therefore, the OPS ONoC system is developed slowly.
At present, most optical buffers in the industry use a solution of fiber loops, and a basic unit of an optical buffer temporarily stores an optical signal using a 2×2 optical switch plus a recirculation fiber loop (as shown in FIG. 1A). Further, an optical switch at an entrance of the optical buffer is controlled to be in an on state such that the optical signal enters the recirculation fiber loop, and when the optical signal needs to be output, an optical switch at an exit of the optical buffer is controlled to be in an on state such that the optical signal is output from the optical buffer. An optical buffer including such cascaded basic units is shown in FIG. 1B. When a newly input optical signal enters a first 2×2 optical switch from an entrance on a left side, if a recirculation fiber loop corresponding to the first optical switch already stores first optical signal data, a controller opens a lower right end of the first optical switch, the first optical signal data enters a second 2×2 optical switch through the lower right end of the first optical switch. If a recirculation fiber loop corresponding to the second optical switch also already stores second optical signal data, the controller opens a lower right end of the second optical switch, the second optical signal data enters a next 2×2 optical switch through the lower right end of the second optical switch, and until a recirculation fiber loop corresponding to a particular optical switch stores no optical signal data, an upper right end of this optical switch may be controlled to be opened, and the newly input optical signal enters a recirculation fiber loop through the upper right end of this optical switch such that the newly input optical signal is circularly transmitted in the recirculation fiber loop, that is, a storage function is implemented.
In researches on the prior art, it is found that the prior art has at least the following problems.
All existing optical buffers prolong a transmission time of optical data in a manner of increasing a length of a fiber. However, because a transmission rate of light in the fiber approaches to the speed of light, a fiber delay solution has disadvantages of a small capacity, a large size, and a difficulty in implementation of monolithic integration. The existing optical buffer generally uses a first in first out storage manner, and when an optical signal needs to enter a recirculation fiber loop of a next optical buffer unit through an optical switch of a particular optical buffer unit, and an optical signal temporarily stored in are circulation fiber loop of the particular optical buffer unit exactly needs to be output, the two optical signals are caused to conflict with each other at an output end of a lower right end of the optical switch corresponding to the particular optical buffer unit. Therefore, it is impossible to implement unordered random storage and reading of an optical signal.